CZI Essential Open Source Software for Science (EOSS) Award for 3D Slicer Internationalization

It is my distinct pleasure to announce that we have been awarded an Essential Open Source Software for Science (EOSS) grant from the Chan Zuckerberg Initiative (CZI), a philanthropy led by Facebook founder Mark Zuckerberg and his wife Dr. Priscilla Chan. The grant will support the new “3D Slicer in My Language” project to increase the accessibility of 3D Slicer in non-English speaking countries. We are thrilled to start developing a French version of 3D Slicer in collaboration with Cheikh Anta Diop University in Senegal thanks to the award. In the future, we plan to translate 3D Slicer to other languages to empower members of the global Slicer community to analyze their own data in their own language.


Clap clap clap!!! Congratulations!!! If you need some help with the spanish language I will be extremely glad to help.

A post was split to a new topic: Fail to import DICOM data with special characters in it

Hi, spujol,

The 3D slicer in My Language project is interesting!
What is the current status of this project?
I am a Japanese, so I can help you to translate strings to Japanese language.
Multi-byte character sometimes cause problems like it does not work with paths including multi-byte characters. When you complete the project, I can strongly recommend 3D slicer to my colleagues and friends.

thank you,

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Dear Esteban,

Thank you for your interest in the Slicer in My Language project. We’d be happy to get your help with the Spanish version of Slicer.


Dear Aki,

Thank you for your interest in the 3D Slicer in My Language project. The project has just started and we’d be happy to get your help with the Japanese version of Slicer.


I come from China. If I need to translate into Chinese, I can help

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Dear Luping,

Thank you for your interest in the 3D Slicer in My Language project. We’ll be happy to welcome your contribution to the Chinese version of Slicer.


We have created a project on Crowdin for translating Slicer. Anybody can register a user at and start submitting translations for the Slicer project. Please give it a try and let us know how things work. Probably these translations will be available for Slicer Preview Release users in a few weeks. Update: We use Weblate for managing the translations - see details below.

For anyone interested in technical details of where the translations are stored and how language packs will be generated, see this discussion.

I come from China.Our team has completed the Chinese translation of version 4.8.1.You can add Cao Yufu WeChat to discuss together.
WeChat: caoyufu

Chinese Forum:

hi @cyufu ! Thank you for joining the conversation. I see there is some Chinese being contributed to crowdin and that you have an account there now. Would be willing to serve a proofreader to approve proposed translations? It will be very helpful to build on your experience.

3DSlicer is my favorite software and I would love to do the job.

Excellent! I changed your crowdin account to be a proofreader so I think that should let you approve the proposed translations. Thank you!

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We added a new extension that allows translators to see the translation results immediately. It can download and install nightly translations with a single click. It can also install latest translations that are downloaded from Crowdin website.

See setup and usage instructions on the extension’s website.

Currently, it requires downloading and installing the Qt toolkit, which is not very convenient (it can take 10-15 minutes). In the near future we will remove this requirement - see details here.

Any feedback and suggestions are welcome.

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A few updates about recent developments.

1. Switch to Weblate

After lengthy discussions and testing, we switched the online translation file editing platform from Crowdin to Weblate.

Crowdin was simple to set up but even after a few weeks we ran into problems due to limitations in feature set and configurability - which were not issues on Weblate. Crowdin most important limitations for use included:

  • Lack of attribution: While Crowdin internally keeps track of who added a translation, that information is not available in our github repository. Therefore, contributions of translators cannot be properly publicly acknoledged. In contrast, Weblate properly sets contributor information in each commit in our github repository, see example.
  • Lack of open access: Crowdin website required registration, even for just viewing the site content. In contrast, Slicer project on Weblate can be accessed publicly, without user registration.
  • Limited bulk data download: Crowdin required manual download of translation files and limited multi-language downloads to managers. In contrast, Weblate allows anyone downloading one or more language packs using simple web requests (this allows single-click language file update in LanguagePacks extension).
  • Insufficient access control granularity. Crowdin only has 3 fixed roles (translator, proofreader, manager), and we could not configure the site to fulfill our requirements (for example glossary was only editable by managers, while we wanted to allow the community to build the glossary). In contrast, Weblate has fine-grained access control, with customizable roles and permissions.
  • Limitations in size and versioning of translations: Crowdin’s free service only supports 60k words and 1 branch for translation. This would be most likely sufficient for translating Slicer core, but not for translating documentation; and would have required workarounds for managing translations of multiple Slicer versions. In contrast, Weblate supports 10k strings and unlimited number of branches. There are examples of Weblate being used for translating documentation hosted on read-the-docs.
  • Crowdin is closed-source, users do not have the option for self-hosting (maybe except some very expensive enterprise contracts). In contrast, Weblate is open-source and can be self-hosted for free.

Currently, we still accept translations from Crowdin, but we will close that project in about a week.

From now on, please add/edit Slicer translations on Weblate.

Instructions for creating and testing translations are provided in the LanguagePacks extension documentation. If you have any questions, please post a new topic (use the i18n tag to indicate that your question is related to internationalization).

2. New “Find text” tool for finding text displayed in Slicer on Weblate website

A convenient tool is added to LanguagePacks extension that allows quickly grabbing text from the Slicer user interface and open look it up on the Weblate website:

See detailed instructions here.

3. Next steps

Currently, all text that are marked as translatable in C++ source code and in .ui files are translatable. We are working on making all strings translatable (CLI modules, Python scripts, various dynamically generated strings).

You can track the progress of our work here:

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